Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Science > Chemistry > Flashcards

Chemistry Flashcards

0
Q

Features of metamorphic rock:

A
  • Hard
  • May contain bands of crystals
  • Must be made by high temp and pressure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

Features of sedimentary rocks:

A
  • They are crumbly
  • They often have fossils
  • They’re porous (have gaps)
  • Found in seas and lakes
  • Often in layers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Features of igneous rock:

A
  • Formed from molten rock
  • Very hard and have crystals
  • If it cools slowly, it has large crystals, if it cools quickly, it will have small crystals.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is acid rain?

A

Acid rain is when sulphur from burnt fossil fuels is released into the atmosphere. It then dissolves with rain water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is catalytic converter?

A

A device put in a car’s exhaust system to convert harmful pollutants into harmless stuff.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the states of matter?

A

Solid, liquid and gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Features of matter

A

Solids :
Particles are very close together
Particles are held together by strong forces of attraction
Particles vibrate but have fixed positions

Liquids:
Particles are quite close together
Articles are held together by forces of attraction
Particles more relative to each other

Gas:
Particles are far apart from each other
Very small force of attraction
Move rapidly in different directions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why do solids have definite volume?

A

Because they are hard to compress

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a soluble?

A

A solid which dissolves in a liquid e.g. Salt and water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a solvent?

A

Once a substance, usually a solid, has dissolved the liquid (often water) is called the solvent.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a solute?

A

The substance which has dissolved

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does insoluble mean?

A

It means a substance cannot dissolve in the solvent.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Does temperature affect the solubility, and how.

A

Yes.
The higher the temp, the more soluble the substance becomes. It quickens the effect of dissolving. This is because the particles are moving faster so the substance will dissolve fast.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a saturated solution?

A

If no more solute can dissolve in a solvent, it is known as a saturated solution.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens to the mass of the solution?

A

It stays the same

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the mingling of particles called?

A

Diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why do we smell things across the room e.g. perfume?

A

Because the scent particles are diffusing through the air to your nose.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What’s expansion

A

When particles are heated, they move more. This means the substance grows bigger (expands.)

Vies versa it can get cooler and contract.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Properties of metal. Say at least 4:

A
  • Good conductors of heat
  • Good conductors of electricity
  • High melting and boiling points (besides mercury)
  • Strong and dense
  • Malleable (can be hammered into shape)
  • Ductile (can be drawn into wires)
  • May be mixed together to form useful alloys
  • Shiny - when freshly cut
  • Sonorous (ping when hit)
  • Are magnetic
    *
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Can non-metals conduct electricity?

A

Only carbon when in graphite form.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is needed for iron to rust?

A

Water and oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is sacrificial protection?

A

When a more reactive metal is used to stop corrosion (rusting.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

When a substance is burned (combustion,) it reacts with the air. What does it become?

A

An oxide
E.g. Magnesium becomes magnesium oxide
2mg + O2 > 2MgO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Order of reactive metals:

Name at least one from each section.

A

Potassium (K)
Sodium (Na)
Calcium (Ca)
Carbon (C)

Zinc   (Zn)
Iron (Fe)
Lead (Pb)
    Hydrogen (H)
Copper (Cu)
Gold (Au)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the rule for displacement reactions?

A

The more reactive metal displaces the less reactive metal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Chart of indicators:

A

Indicator Acid Neutral Alkali

Universal red green purple
Blue litmus red blue blue
Red litmus red red blue
Phenolphthalein
colourless colourless pink

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the pH of a strong acid?

A

pH 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the pH of a neutral?

A

7

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the pH of a weak alkali

A

8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the pH of the strongest alkali

A

14

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Name an oxide and a hydroxide which react with acid to make salt and water…

A

Copper oxide

Sodium hydroxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Metals react with acids to from…

A

Salt and hydrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Test for CO2

A

Limewater bubbles and turns milky

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Test for oxygen

A

Light a splint and hold it in the testube. It will relight.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Test for hydrogen

A

The splint in the gesture makes a pop sound. The “pop test”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What are the 3 most common gasses?

A

Carbon dioxide
Hydrogen
Oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are the 2 differences between a mixture and a compound?

A

Mixtures are easier to separate and don’t have a fixed position.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How do mixtures melt?

A

The different component melt at different times so it takes a while
E.g. Some parts of butter melt while others are solid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Rocks are a mixture of…

A

Minerals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

When does a compound melt?

A

E.g. Ice.

It remains the same temp until it has melted to a liquid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is filtration?

A

It’s used to separate a solid from a liquid. The solid on the filter paper is called the residue.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What happens in filtration and evaporation?

A

After filtration, the solution of solvent and solute is separated by evaporation e.g. Salt and water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What’s chromatography?

A

It’s to separate different coloured dyes. A spot of ink is put on filter paper and the water separates it because each dye has a different solubility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What’s distillation?

A

When a solution is heated, water boils and water vapour is formed. The vapour cools and condenses to a liquid in a beaker and is called ‘distiller water’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What’s fractional distillation?

A

To separate two or more liquids from each other e.g. Water and alcohol because they have different boiling points.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Are the parts of a mixture joined together?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

When atoms from 2+ different elements join together, they make…

A

A compound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

2+ atoms may form…

A

A molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Main 3 signs of a chemical reaction:

A

Change in temperature
Change in colour
Gas produced - bubbles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Atoms of the same element form molecules…

A

Of the same element

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Atoms from 2+ elements joined form molecules of…

A

A compound.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What do these non-metals become once they become compounds?

Oxygen 
Fluorine
Bromine 
Iodine
Sulphur
A 
Oxide
Fluoride
Bromide
Iodide
Sulphide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What is OH?

A

Hydroxide

Sodium hydroxide = NaOH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What is sulphate and carbonate as a symbol?

A

SO4

CO3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What does the di in dioxide mean?

A

2 as in 2 oxygen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What is the equation for carbon dioxide?

A

Carbon + oxygen = carbon dioxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

How many hydrogen atoms are in water?

A

2

H2O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What elements are present in the formula: CuSO4 ?

A

Copper 1
Sulphate. 1
Oxygen 4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Balance C + CO2 = CO

A

2CO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What’s an ionic bond?

A

A bond formed between metals and non-metals by giving or gaining electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What is an atom made of?

A

Protons (positive)
Neutrons (neutral)
Electrons (negative)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What’s an element?

A

Something made entirely of the same atom and can’t be broken down into anything more. They’re pure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What’s a covalent bond?

A

A bond formed between 2 non-metals by sharing electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What does a word with …ide mean?

A

2 elements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What does a word with …ate mean?

A

3 elements (including oxygen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What type of elements are group 1?

A

Alkaline metals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What type of elements are group 7?

A

Halogen non-metals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What type of elements are group 0?

A

Noble unreactive gases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

How do you draw an element?

A

Circles for shells

Crosses as the electrons, drawn on in quarters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Balancing equations:
Balance
Hydrogen + Oxygen -> Water

A

H2 + O2 -> H2 O
H2 + O2 -> 2H2 O
2H2 + O2 -> 2H2 O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

What’s an isotope?

A

A different form of the same element

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

1
H
1

What does the bottom number mean?

A

Atomic (proton) number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

1
H
1
What does the top number mean?

A

Atomic mass (number of protons and neutrons)

73
Q

How do you know how many electrons are in an element?

A

The number of electrons is the same as the number of protons (positives and negatives attract)

74
Q

What are the charges of protons, neutrons and electrons?

A

Protons +1
Neutrons 0
Electrons -1

75
Q

What is the mass of protons, neutrons and electrons?

A

1
1
0

76
Q

What’s a diatomic molecule?

A

A molecule that travels in pairs e.g. Oxygen

77
Q

What does limestone (CaCO3) form when heated?

A

Calcium oxide and carbon dioxide

CaO & CO2

78
Q

What does calcium oxide (CaO) form when water is added?

A

Calcium hydroxide

Ca(OH)2

79
Q

What does limestone (CaCO3) form when it’s powdered and heated with clay?

A

Cement

80
Q

Is limestone acid or alkaline?

A

Alkaline

81
Q

What is concrete?

A

A mix of cement and water with sand and gravel.

82
Q

How does a self heating can work?

A

The can has a gap between the cup wall and the wall which holds the food or drink. In the gp, there is a sachet of calcium oxide which, when the can is opened and water is released in the gap, will react with the calcium oxide and produce heat.

83
Q

What’s the name of a reaction which creates heat?

A

Exothermic

84
Q

What happens when limestone is heated?

A

It glows and breaks down into a power substance. This is called thermal decomposition.

85
Q

What’s thermal decomposition?

A

A substance breaking down due to heat.

86
Q

If hydrochloric acid is used, what does It become?

A

A chloride

87
Q

If sulphuric acid is used, what does It become?

A

Sulphate

88
Q

If nitric acid is used, what does It become?

A

Nitrate

89
Q

3 carbonate examples:

A

Sodium carbonate
NaCO3

Copper carbonate
CuCO3

Zinc carbonate
ZnCO3

90
Q

What’s a carbonate?

A

A salt

91
Q

Whats cement made of?

A

Limestone and clay

92
Q

Cement and sand makes…

A

Mortar

93
Q

How does cement form crystal ‘finger’ bonds?

A

It reacts with water (called hydration)

94
Q

How does cement get harder over time?

A

Hydration takes a while so, even if the cement is strong, more bonds will form and it will become stronger.

95
Q

Does more sand and gravel (concrete) make the mixture stronger or weaker?

A

Weaker. Purer cement is stronger.

96
Q

3 main pros (for) of quarrying:

A

Limestone is on demand and is needed everyday for daily use.

It provides jobs

Helps the economy as it provides/makes money

97
Q

3 main cons (against) of quarrying?

A

They’re ugly and unpopular, reducing numbers such as tourists and house prices

They cause a lot of traffic, noise and pollution which affects locals

It destroys animals, habitats, wildlife and a natural area which can never be properly replaced

98
Q

What’s quarrying/a quarry?

A

An area like a deep pit where stone and various other materials are extracted from the soil.

99
Q

What’s aggregate?

A

Small stones and gravel (used for concrete)

100
Q

What’s a mineral?

A

A solid element or compound found in the earth’s crust

101
Q

What’s an ore?

A

A rock or mineral containing enough metal to make extraction worthwhile.

102
Q

What can copper be used for?

A

Coins, piping, wiring, pins.

103
Q

What can iron be used for?

A

Tubes, cutlery, cans, steel.

104
Q

What can aluminium be used for?

A

Cooking foil, drink cans, bottle tops.

105
Q

What can sulphur be used for?

A

Fertilizer, detergents, to harden rubber.

106
Q

What is zinc used for?

A

Protection from rust

107
Q

What is gold used for?

A

Jewellery and computer circuits.

108
Q

What is a displacement reaction?

A

When a more reactive metal boots out a less reactive metal e.g.

Iron + copper sulphate = iron sulphate + copper

109
Q

What are good sources of carbon?

A

Biomass, coal and wood

110
Q

What is reduction?

A

When oxygen is removed from from a substance e.g.

Metal oxide + reduction = metal

111
Q

What is oxidisation?

A

When oxygen is added to a substance e.g.

Copper oxide + carbon = carbon dioxide + copper

112
Q

What is more reactive? Carbon or copper?

A

Carbon

113
Q

2CuO + C = 2Cu + CO2

What is reduced and what is oxidated?

A

Copper oxide is reduced and carbon is oxidised.

114
Q

Why can we use carbon to extract copper from copper oxide?

A

Because carbon is more reactive.

115
Q

How do you concentrate on ore?

A

Heat it, resulting in thermal decomposition

116
Q

What is a blast furnace?

A

It is like a oven, heated up to 1900’c, in the form of a tower into which a blast of hot compressed air can be introduced from below. Such furnaces are used chiefly to make iron from a mixture of iron ore, coke, and limestone.

117
Q

How does a blast furnace work?

A

Carbon/coke/coal, limestone and iron ores are put into the top. Hot air is blasted from the bottom.

Carbon/coke + oxygen/air = carbon dioxide

Carbon dioxide + carbon = carbon monoxide

Iron oxide + carbon monoxide = iron + carbon dioxide

Limestone is used to remove impurities in the form of slag.

Iron is reduced. Carbon is oxidised.

118
Q

How does limestone purify iron in the blast furnace?

A

It reacts with the oxygen and becomes oxidised.

119
Q

Properties of cast iron (4):

A

Molten iron from the blast furnace
96% iron - not pure - contains carbon and slag
Hard, strong, doesn’t rust, brittle - arranged in an irregular pattern
Used for strength not flexibility

120
Q

Properties of wrought iron (3):

A

100% iron - pure
Very soft - arranged in a regular pattern
Malleable

121
Q

Properties of stainless steel (3):

A

Doesn’t rust
Alloy - nickel and chromium
Expensive

122
Q

Properties of low carbon steel (3):

A

0.2% carbon
Malleable
Used for car bodies and wires

123
Q

Properties of high carbon steel (3):

A

0.6 - 1.5% carbon
Very hard
Used for tools

124
Q

Properties of metals (9):

A 
Good conductors of heat
Good conductors of electricity
High melting and boiling points (except mercury)
Shiny (when freshly cut - lustrous)
Can be malleable 
Can be ductile
Some are magnetic
Some are sonorous 
Some are strong and dense
125
Q

What is electrolysis?

A

It is another way to extract metals, which are very reactive, by splitting up a substance or compound by using electricity.
It is chemical decomposition produced by passing an electric current through a liquid or solution containing ions.

Electrolysis is the process by which ionic substances are broken down into simpler substances using electricity. During electrolysis, metals and gases may form at the electrodes.

What is electrolysis?
Ionic substances contain charged particles called ions. For example, lead bromide contains positively charged lead ions and negatively charged bromide ions.
Electrolysis is the process by which ionic substances are decomposed (broken down) into simpler substances when an electric current is passed through them. (Ionic bond/substance is between a metal and a non metal)
For electrolysis to work, the ions must be free to move. Ions are free to move when an ionic substance is dissolved in water or when melted. For example, if electricity is passed through molten lead bromide, the lead bromide is broken down to form lead and bromine.

Here is what happens during electrolysis:
Positively charged ions move to the negative electrode during electrolysis. They receive electrons and are reduced.
Negatively charged ions move to the positive electrode during electrolysis. They lose electrons and are oxidised.
The substance that is broken down is called the electrolyte.
(The cathode is negative and the anode is positive)

126
Q

What is bioleaching?

A

It is an alternative way to extract copper by using low grade copper ores (which aren’t worth while) and a combination of biological and chemical processes. Sulphuric acid dissolves the copper ions and runs of as slag where it’s collected and extracted by displacement or electrolysis; all due to bacteria.

127
Q

Pros and cons of bioleaching:

A

Pros
Low cost
Less pollution and energy
Doesn’t need much land (doesn’t scar the environment)

Cons
Doesn’t recover precious metals
Sometimes acid is needed which can cost a lot
Sometimes bacteria itself produces too much acid and must be neutralised which costs
Slow

128
Q

What is phytomining?

A

It is another way to extract copper from it’s ore. This is done by plants absorbing the elements through their roots and into the stem and leaves when they become more concentrated and are then burned, producing an ash rich with the compound.

129
Q

Pros and cons of phytomining:

A 
Pros
Recovers precious metals
Takes metals out of the ground which helps the environment
Not very expensive
Easy to monitor
Cons
Dependent on the weather & survival of plants
Requires a lot of land
Takes a long time
Hard to make completely pure
130
Q

Why must we recycle metals?

A 
Saves energy
Saves money
Doesn't require digging
Conserves the environment 
We are running out of metals
162
Q

What’s crude oil?

A

It’s a very important fossil fuel used to make plastics made up of a mixture of different compounds.

163
Q

How is crude oil made?

A

It’s made from the bodies of tiny sea creatures and plants that died roughly 150 million years ago.
They were buried beneath layers of sand and stilt on the sea bed and didn’t decay normally as bacteria feeding on them had little to no oxygen. As the pressure and temperature increased, oil was formed.
Crude oil itself is useless therefore must be separated.
Natural gas is usually found with crude oil.

164
Q

What is crude oil separated into?

A

Fractions

Different groups of hydrocarbons based on their boiling points.

165
Q

What are alkanes and what is their formula?

A

They are saturated hydrocarbons made from crude oil.

Cn 2n+2

166
Q

What are alkenes and what is their formula?

A

They are hydrocarbons with a carbon double bond meaning they can separate and become saturated therefore alkenes are unsaturated.

Cn H2n

167
Q

What are the first 5 alkanes?

A 
Methane - CH4
Ethane - C2H6
Propane - C3H8
Butane - C4H10
Pentane - C5H12
168
Q

What’s fractional distillation?

A

A process used to separate a mixture of liquids that have different boiling points.
This can be used for crude oil as crude oil is made up of different compounds with different boiling points.

169
Q

What type of fuel is found at the top of the fractional distillation column?
(Coolest part of the column)

A

Fuels with small molecules which are colourless, runny and highly flammable.

170
Q

What type of fuel is found in the middle of the fractional distillation column?

A

Fuels with medium sized molecules which are a yellowish colour, are quite thick and quite hard to light - a bit of smoke.

171
Q

What type of fuel is found at the bottom of the fractional distillation column?
(Hottest part of the column)

A

Fuels with large molecules which are a dark orange colour, are quick thick (viscous) and are difficult to light - quite a smokey flame.

172
Q

What are the effects of burning hydrocarbons on the environment?
(Negative)

A

1) When hydrocarbons and completely combusted, carbon dioxide (and water) is produced which contributes to global warming and greenhouse gasses as well as minority contributing to acid rain.
2) If incomplete combustion occurs - when it hasn’t completely burned or there isn’t enough oxygen/air or the amount is limited, carbon monoxide is produced which is an extremely deadly, toxic gas.
3) Ash and carbon (soot) may form too due to incomplete combustion. This can then form solid particles containing carbon and hydrocarbons, known as particulates, which cause global dimming, meaning they reflect the sunlight (back).
4) Fossil fuels often have sulphur and/or nitrogen compounds which, when burned, can combine with the air at high temperatures to form acid rain.

173
Q

How can the negative environmental effects of burning hydrocarbons be reduced?

A

Sulphur can be removed from waste gasses as the waste gasses are mixed with powdered limestone. The SO2 then reacts with it to form calcium sulphate.

Catalytic converters for cars also stop/reduce carbon monoxide and nitrogen oxide from going into the environment and filters can be used to remove particulates.

174
Q

What’s the order of fuels from a fractional distillation column?
Top (cool) to bottom (hot).

A 
Petroleum gases
Petrol
Kerosine
Diesel
Lubricating oil
Heavy fuel oil
Bitumen
175
Q

What’s the type of reaction that releases energy from a fuel?

A

Combustion

176
Q

How is petrol separated from the mixture of hydrocarbons in crude oil?

A

As crude oil itself is useless, it must be separated into fractions.
These fractions, such as petrol, are achieved by fractional distillation. They way this process works is that, within a large column, crude oil is heated to approx 400°C causing most of the compounds within crude oil to evaporate into vapours. Small molecules with low boiling points are collected at the top and large molecules with high boiling points are collected at the bottom.
Those with large molecules that don’t evaporate remain liquid.
As the different compounds have different melting and boiling points, they also cool and condense at different stages, resulting in separated fractions.
As petrol has quite small molecules and and a low boiling point, it condenses at the top of the column, the coolest part, turning back into a liquid but now it is a fraction on it’s own - separated.

177
Q

What is cracking?

A

The process when large molecules and heated and thermally decomposed, forming smaller, more useful hydrocarbons using a catalyst (something which speeds up an experiment) often forming alkenes.
An example of this is when decane goes through the process of cracking, forming smaller, more useful substances.

Decane -heat-> octane + ethene
C10H22 -> C8H18 + C2H4

178
Q

What is formed when large molecules go through cracking?

A

An alkene is formed.

179
Q

What is the test for unsaturated hydrocarbons (alkenes)?

A

The bromine water test when (yellow) bromine water is added to the substance and changes colour (to colourless) if an alkene is present or not.

180
Q

What are monomers?

A

Small reactive molecules that react together in repeating sequences to form a very large molecule (polymer).

181
Q

What’s a polymer?

A

A substance made from very large molecules made up of a chain/many repeating units e.g. Poly ethene
Big molecules made up from small molecules - monomers.

182
Q

What is polymerisation?

A

The reaction of monomers (small molecules) to make a polymer (large molecule).

183
Q

How a polymers drawn?

E.g. Ethene -> poly ethene

A

H H
\ /
C = C Monomer = means double bond
/ \ n. means number
n. H H

Polymerisation =

   (  H        H  )
   (   \         /   )
   (  - C - C -  )                
   (   /         \   )                            
   (  H        H  ) n.
184
Q

How are plastics made?

A

Plastics are made by joining small molecules together end to end to make long chain molecules. The small single molecules are called monomers and the long chain molecules are called polymers. (Poly meaning many within chemistry).

So the plastic poly-ethene is made from ethene (monomer). The process of joining the molecules up is called polymerisation.

185
Q

What do the properties of plastics depend on?

A

The arrangement of the polymer chains

186
Q

What are the 2 main types of plastics and how are their chains arranged?

A

Thermo-softening and thermosetting.

Thermo-softening polymer chains are described like spaghetti as they are loose and everywhere with weak forces between separate polymer chains.

Thermosetting polymer chains are rigid and are fixed together by strong bonds called cross linking.

187
Q

What are the properties of thermo-softening plastics?

A

Become soft and melt when heated
Used when plastics need to be re shaped - can be re shaped by cooling and heating
Can be recycled
It will burn / ignite
Long polymer chains not cross linked
Used in bags, gutters and buckets (examples are polythene, PVC and Perspex)

188
Q

What are the properties of thermosetting plastics?

A

Do not melt on heating but char
Used when the object is likely to come into contact with heat
Cannot be recycled
Cannot be re shaped by heating and cooling
Long polymer chains cross linked
Used for light fittings, saucepan handles, kitchen work surfaces, tires etc (examples include Bakelite, melamine and Formica)

189
Q

What are shape memory polymers?

A

Polymers which have the ability to, once they’ve been shaped, change back to their original shape when the stimulus (commonly temperature) triggers the shape to change. It’s often used for stitching wounds as it is heated by the body and can can shape to form the body.
Smart polymers can also change colour.

190
Q

How are polymers used for waterproofing?

A

Fibres used for fabrics are often coated with polymers to make them waterproof.

191
Q

How are polymers used for hydrogels?

A

(As polymers have properties that make them specially suited for their purpose) polymers within hydrogels are highly hydrophilic, meaning they’re attracted to water, which results in them being very flexible and absorbent.
Used for nappies and wound dressings.

192
Q

What are the 2 main processes to produce ethanol.

A

Fermentation and hydration of ethene.

193
Q

How does fermentation work to produce ethanol?

A

Yeast is added to glucose (sugar)
Enzymes (biological catalysts) cause the sugar to convert to ethanol and carbon dioxide.

Glucose -yeast-> ethanol + carbon dioxide

C6H12O6 -> 2C2H5OH + 2CO2

194
Q

How does the hydration of ethene produce ethanol?

A

Ethene, obtained from the distillation and cracking of crude oil, is reacted with steam at a high pressure and temperature in the presence of a catalyst.

Ethene + water -high pressure & phosphoric acid catalyst-> ethanol

C2H4 + H2O -> C2H5OH

195
Q

What is the issue with many (non-biodegradable) polymers?

A

The waste isn’t broken when left in the environment. This means it’s unsightly, can harm wildlife and, even when out in landfill sites, it takes up a lot of valuable space.

196
Q

We are using more plastics that are biodegradable. What does this mean?

A

Biodegradable plastics can decompose and break down due to microorganisms in the soil.

197
Q

How can cornstarch be used to help plastic disposal problems?

A

Cornstarch can be mixed into the plastic so that microorganisms can break down the cornstarch so the plastic breaks down into very small pieces that can be mixed with soil and compost.

It can help make biodegradable plastics.

198
Q

How can cornstarch be used to help plastic disposal problems?

A

Cornstarch can be mixed into the plastic so that microorganisms can break down the cornstarch so the plastic breaks down into very small pieces that can be mixed with soil and compost.

It can help make biodegradable plastics.

199
Q

We are using more plastics that are biodegradable. What does this mean?

A

Biodegradable plastics can decompose and break down due to microorganisms in the soil.

200
Q

What is the issue with many (non-biodegradable) polymers?

A

The waste isn’t broken when left in the environment. This means it’s unsightly, can harm wildlife and, even when out in landfill sites, it takes up a lot of valuable space.

201
Q

How does the hydration of ethene produce ethanol?

A

Ethene, obtained from the distillation and cracking of crude oil, is reacted with steam at a high pressure and temperature in the presence of a catalyst.

Ethene + water -high pressure & phosphoric acid catalyst-> ethanol

C2H4 + H2O -> C2H5OH

202
Q

How does fermentation work to produce ethanol?

A

Yeast is added to glucose (sugar)
Enzymes (biological catalysts) cause the sugar to convert to ethanol and carbon dioxide.

Glucose -yeast-> ethanol + carbon dioxide

C6H12O6 -> 2C2H5OH + 2CO2

203
Q

What are the 2 main processes to produce ethanol.

A

Fermentation and hydration of ethene.

204
Q

How are polymers used for hydrogels?

A

(As polymers have properties that make them specially suited for their purpose) polymers within hydrogels are highly hydrophilic, meaning they’re attracted to water, which results in them being very flexible and absorbent.
Used for nappies and wound dressings.

205
Q

How are polymers used for waterproofing?

A

Fibres used for fabrics are often coated with polymers to make them waterproof.

206
Q

What are shape memory polymers?

A

Polymers which have the ability to, once they’ve been shaped, change back to their original shape when the stimulus (commonly temperature) triggers the shape to change. It’s often used for stitching wounds as it is heated by the body and can can shape to form the body.
Smart polymers can also change colour.

207
Q

What are the properties of thermosetting plastics?

A

Do not melt on heating but char
Used when the object is likely to come into contact with heat
Cannot be recycled
Cannot be re shaped by heating and cooling
Long polymer chains cross linked
Used for light fittings, saucepan handles, kitchen work surfaces, tires etc (examples include Bakelite, melamine and Formica)

208
Q

What are the properties of thermo-softening plastics?

A

Become soft and melt when heated
Used when plastics need to be re shaped - can be re shaped by cooling and heating
Can be recycled
It will burn / ignite
Long polymer chains not cross linked
Used in bags, gutters and buckets (examples are polythene, PVC and Perspex)

209
Q

What are the 2 main types of plastics and how are their chains arranged?

A

Thermo-softening and thermosetting.

Thermo-softening polymer chains are described like spaghetti as they are loose and everywhere with weak forces between separate polymer chains.

Thermosetting polymer chains are rigid and are fixed together by strong bonds called cross linking.

210
Q

What do the properties of plastics depend on?

A

The arrangement of the polymer chains

211
Q

How are plastics made?

A

Plastics are made by joining small molecules together end to end to make long chain molecules. The small single molecules are called monomers and the long chain molecules are called polymers. (Poly meaning many within chemistry).

So the plastic poly-ethene is made from ethene (monomer). The process of joining the molecules up is called polymerisation.

Science (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions